<?php
!function_exists('readover') && exit('Forbidden');

/**
 * GIF图片生成器
 * 
 * @package Image
 */
class GIFEncoder {
	/**
	 * GIF header 6 bytes, Constant
	 * @var string
	 */
	var $GIF = "GIF89a";
	/**
	 * Encoder version, Constant
	 * @var string
	 */
	var $VER = "GIFEncoder V2.06";
	
	var $BUF = array();
	var $LOP = 0;
	var $DIS = 2;
	var $COL = -1;
	var $IMG = -1;
	
	var $ERR = array(
		'ERR00' => "Does not supported function for only one image!",
		'ERR01' => "Source is not a GIF image!",
		'ERR02' => "Unintelligible flag ",
		'ERR03' => "Could not make animation from animated GIF source"
	);
	
	function GIFEncoder($GIF_src, $GIF_dly, $GIF_lop, $GIF_dis, $GIF_red, $GIF_grn, $GIF_blu, $GIF_mod) {
		if (!is_array($GIF_src) && !is_array($GIF_tim)) {
			printf("%s: %s", $this->VER, $this->ERR['ERR00']);
			exit(0);
		}
		$this->LOP = ($GIF_lop > -1) ? $GIF_lop : 0;
		$this->DIS = ($GIF_dis > -1) ? (($GIF_dis < 3) ? $GIF_dis : 3) : 2;
		$this->COL = ($GIF_red > -1 && $GIF_grn > -1 && $GIF_blu > -1) ? ($GIF_red | ($GIF_grn << 8) | ($GIF_blu << 16)) : -1;
		
		for ($i = 0; $i < count($GIF_src); $i++) {
			if (strtolower($GIF_mod) == "url") {
				$this->BUF[] = fread(fopen($GIF_src[$i], "rb"), filesize($GIF_src[$i]));
			} elseif (strtolower($GIF_mod) == "bin") {
				$this->BUF[] = $GIF_src[$i];
			} else {
				printf("%s: %s ( %s )!", $this->VER, $this->ERR['ERR02'], $GIF_mod);
				exit(0);
			}
			if (substr($this->BUF[$i], 0, 6) != "GIF87a" && substr($this->BUF[$i], 0, 6) != "GIF89a") {
				printf("%s: %d %s", $this->VER, $i, $this->ERR['ERR01']);
				exit(0);
			}
			for ($j = (13 + 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07))), $k = true; $k; $j++) {
				switch ($this->BUF[$i]{$j}) {
					case "!":
						if ((substr($this->BUF[$i], ($j + 3), 8)) == "NETSCAPE") {
							printf("%s: %s ( %s source )!", $this->VER, $this->ERR['ERR03'], ($i + 1));
							exit(0);
						}
						break;
					case ";":
						$k = false;
						break;
				}
			}
		}
		GIFEncoder::GIFAddHeader();
		for ($i = 0; $i < count($this->BUF); $i++) {
			GIFEncoder::GIFAddFrames($i, $GIF_dly[$i]);
		}
		GIFEncoder::GIFAddFooter();
	}
	
	function GIFAddHeader() {
		$cmap = 0;
		if (ord($this->BUF[0]{10}) & 0x80) {
			$cmap = 3 * (2 << (ord($this->BUF[0]{10}) & 0x07));
			$this->GIF .= substr($this->BUF[0], 6, 7);
			$this->GIF .= substr($this->BUF[0], 13, $cmap);
			$this->GIF .= "!\377\13NETSCAPE2.0\3\1" . GIFEncoder::GIFWord($this->LOP) . "\0";
		}
	}
	
	function GIFAddFrames($i, $d) {
		$Locals_str = 13 + 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07));
		$Locals_end = strlen($this->BUF[$i]) - $Locals_str - 1;
		$Locals_tmp = substr($this->BUF[$i], $Locals_str, $Locals_end);
		$Global_len = 2 << (ord($this->BUF[0]{10}) & 0x07);
		$Locals_len = 2 << (ord($this->BUF[$i]{10}) & 0x07);
		$Global_rgb = substr($this->BUF[0], 13, 3 * (2 << (ord($this->BUF[0]{10}) & 0x07)));
		$Locals_rgb = substr($this->BUF[$i], 13, 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07)));
		$Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 0) . chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . "\x0\x0";
		
		if ($this->COL > -1 && ord($this->BUF[$i]{10}) & 0x80) {
			for ($j = 0; $j < (2 << (ord($this->BUF[$i]{10}) & 0x07)); $j++) {
				if (ord($Locals_rgb{3 * $j + 0}) == ($this->COL >> 0) & 0xFF && ord($Locals_rgb{3 * $j + 1}) == ($this->COL >> 8) & 0xFF && ord($Locals_rgb{3 * $j + 2}) == ($this->COL >> 16) & 0xFF) {
					$Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 1) . chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . chr($j) . "\x0";
					break;
				}
			}
		}
		
		switch ($Locals_tmp{0}) {
			case "!":
				$Locals_img = substr($Locals_tmp, 8, 10);
				$Locals_tmp = substr($Locals_tmp, 18, strlen($Locals_tmp) - 18);
				break;
			case ",":
				$Locals_img = substr($Locals_tmp, 0, 10);
				$Locals_tmp = substr($Locals_tmp, 10, strlen($Locals_tmp) - 10);
				break;
		}
		
		if (ord($this->BUF[$i]{10}) & 0x80 && $this->IMG > -1) {
			if ($Global_len == $Locals_len) {
				if (GIFEncoder::GIFBlockCompare($Global_rgb, $Locals_rgb, $Global_len)) {
					$this->GIF .= ($Locals_ext . $Locals_img . $Locals_tmp);
				} else {
					$byte = ord($Locals_img{9});
					$byte |= 0x80;
					$byte &= 0xF8;
					$byte |= (ord($this->BUF[0]{10}) & 0x07);
					$Locals_img{9} = chr($byte);
					$this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
				}
			} else {
				$byte = ord($Locals_img{9});
				$byte |= 0x80;
				$byte &= 0xF8;
				$byte |= (ord($this->BUF[$i]{10}) & 0x07);
				$Locals_img{9} = chr($byte);
				$this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
			}
		} else {
			$this->GIF .= ($Locals_ext . $Locals_img . $Locals_tmp);
		}
		$this->IMG = 1;
	}
	
	function GIFAddFooter() {
		$this->GIF .= ";";
	}
	
	function GIFBlockCompare($GlobalBlock, $LocalBlock, $Len) {
		for ($i = 0; $i < $Len; $i++) {
			if ($GlobalBlock{3 * $i + 0} != $LocalBlock{3 * $i + 0} || $GlobalBlock{3 * $i + 1} != $LocalBlock{3 * $i + 1} || $GlobalBlock{3 * $i + 2} != $LocalBlock{3 * $i + 2}) {
				return 0;
			}
		}
		return 1;
	}
	
	function GIFWord($int) {
		return (chr($int & 0xFF) . chr(($int >> 8) & 0xFF));
	}
	
	function GetAnimation() {
		return $this->GIF;
	}
}
?>